[PATCH 5.10 08/49] iommu/amd: Fix sleeping in atomic in increase_address_space()

gregkh
2021-03-10T13:25:16Z

From: Andrey Ryabinin <arbn@yandex-team.com>

commit 140456f994195b568ecd7fc2287a34eadffef3ca upstream.

increase_address_space() calls get_zeroed_page(gfp) under spin_lock with
disabled interrupts. gfp flags passed to increase_address_space() may allow
sleeping, so it comes to this:

BUG: sleeping function called from invalid context at mm/page_alloc.c:4342
in_atomic(): 1, irqs_disabled(): 1, pid: 21555, name: epdcbbf1qnhbsd8

Call Trace:
dump_stack+0x66/0x8b
___might_sleep+0xec/0x110
__alloc_pages_nodemask+0x104/0x300
get_zeroed_page+0x15/0x40
iommu_map_page+0xdd/0x3e0
amd_iommu_map+0x50/0x70
iommu_map+0x106/0x220
vfio_iommu_type1_ioctl+0x76e/0x950 [vfio_iommu_type1]
do_vfs_ioctl+0xa3/0x6f0
ksys_ioctl+0x66/0x70
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x4e/0x100
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by moving get_zeroed_page() out of spin_lock/unlock section.

Fixes: 754265bcab ("iommu/amd: Fix race in increase_address_space()")
Signed-off-by: Andrey Ryabinin <arbn@yandex-team.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210217143004.19165-1-arbn@yandex-team.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Andrey Ryabinin <arbn@yandex-team.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/iommu/amd/iommu.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1503,6 +1503,10 @@ static bool increase_address_space(struc
bool ret = true;
u64 *pte;

+ pte = (void *)get_zeroed_page(gfp);
+ if (!pte)
+ return false;
+
spin_lock_irqsave(&domain->lock, flags);

amd_iommu_domain_get_pgtable(domain, &pgtable);
@@ -1514,10 +1518,6 @@ static bool increase_address_space(struc
if (WARN_ON_ONCE(pgtable.mode == PAGE_MODE_6_LEVEL))
goto out;

- pte = (void *)get_zeroed_page(gfp);
- if (!pte)
- goto out;
-
*pte = PM_LEVEL_PDE(pgtable.mode, iommu_virt_to_phys(pgtable.root));

pgtable.root = pte;
@@ -1531,10 +1531,12 @@ static bool increase_address_space(struc
*/
amd_iommu_domain_set_pgtable(domain, pte, pgtable.mode);

+ pte = NULL;
ret = true;

out:
spin_unlock_irqrestore(&domain->lock, flags);
+ free_page((unsigned long)pte);

return ret;
}